The present invention relates to temperature exchangers which comprise tube plates, namely plates pierced with simple bores or having tubes passing therethrough which open at the surface thereof.
For protecting the faces of such plates or the ends of such tubes against corrosion, erosion and/or temperature phenomena, it is current practice to use pieces called "ferrules" in the form of tubes with turned down circular edge, forming a collar, which are positioned inside the end of the tubes or bores of the tube plate.
So that these "ferrules" may provide maximum protection, their collars must overlap in successive stacks going up to four thicknesses.
This means of protection has numerous disadvantages, more particularly the surface roughness, gaps between the different collar levels and the impossibility of sealing the face formed by the assembly of collars.